In mesh network there is no base station to organize communication between network nodes. Instead, all nodes, or stations, typically use each other's knowledge about surrounding stations in order to communicate. For example if a first station wishes to communicate with a second station but does not know which path should be used to reach the second station, the first station will typically broadcast a data packet comprising a path request (PREQ) for the second station.
The broadcasted data packet will be received by neighboring stations to the first station. The neighboring stations typically determine if the PREQ is addressed to them, and if such is not the case, broadcast it further to other neighboring stations.
This procedure is typically repeated until the second station receives the PREQ and finds its own address in it. Upon determining that the PREQ has found its target, the second station replies by sending a unicast path reply (PREP) to the first station which follows the path the PREQ took to reach the second station in reverse.
Since mesh networks typically are dynamic with stations entering and leaving the network frequently and/or moving around within the mesh network changing their positions, and thereby also the topology of the mesh network, the PREQ/PREP routine is periodically updated and new PREQs/PREPs are sent out.
Since the stations in the mesh network typically are mobile, stations that recently found themselves in areas with good signal quality may suddenly find themselves in areas with bad reception. This may typically lead to that a path using these stations as links may comprise one or more bad links which affects the overall throughput.
To prevent links from breaking, the paths are regularly updated. According to IEEE802.11s/IEEE802.11 Mesh, path requests are broadcasted regularly (e.g. every 5 seconds), and as a PREP is received for each other station indicating a path to that station, that path is used until the next path request is issued. However, as this path may not be the best path, packet loss may occur when using it.
Because of the periodic update of the PREQ/PREP, reactions to bad or broken links may typically be too slow, which results in packet loss.